The TRAF gene family in turbot (Scophthalmus maximus): Identification, characterization, molecular evolution and expression patterns analysis.

Tumor necrosis factor receptor-associated factor (TRAF) is an important structural protein, which can bind to TNF receptors and participate in the regulation of TNF signaling pathway. Nonetheless, few studies have been conducted to investigate the systematic identification of TRAF gene family in teleost and role in innate immunity of turbot (Scophthalmus maximus). In this study, eight TRAF genes, namely SmTRAF2aa, SmTRAF2ab, SmTRAF2b, SmTRAF3, SmTRAF4a, SmTRAF5, SmTRAF6 and SmTRAF7, were identified and annotated in turbot by using bioinformatics methods. Analysis of the phylogenetic, syntenic and molecular evolution demonstrated that all SmTRAF members were evolutionarily conserved in teleost. Domain analysis showed all SmTRAF proteins contained a typical conserved N-terminal RING finger domain. Most SmTRAF proteins contained a MATH domain at the C-terminal, while SmTRAF7 contains seven duplicate WD40 domains. In addition, quantitative real-time PCR was performed to detect the expression patterns of SmTRAFs in tissues from healthy and Vibrio anguillarum infected turbots. The results indicated SmTRAFs had diverse tissue expression patterns and the expression of TRAF gene changed significantly after V. anguillarum infection. This study provided a basis for understanding the roles of TRAFs in the innate immune response of turbot.